When fire investigators suspect an arson, Colorado Bureau of Investigation Agent Jerry Means' phone may ring. He and his partner Riley are one of just three teams in Colorado able to quickly gather what could be key evidence in those crimes.

Riley is an “arson dog" whose job it is to sniff out traces of gasoline, lighter fluid and other accelerants criminals may use to cover up their acts.

"[Arson dogs] take the guesswork out of where we need to take the samples," Means says, talking about forensic work he does at crime scenes.

In April, Means' previous partner, Sadie, retired. She served for seven years and approximately 500 fires.

Means recalls many of them, including the time Sadie, a black labrador, played a key role in helping solve the murders of three children in Colorado Springs.

“Both mom and dad were prosecuted for that case,” Means says, and sentenced to life behind bars.

Sadie was also "quite an ambassador for the state of Colorado,” Means says. And in 2011, Sadie was named the Top Law Enforcement/Arson Dog in the United States by the American Humane Association. She also received a Golden Paws Award from the MaxFund no-kill shelter.

Along the way Sadie became a model. Her likeness was enshrined at the National Fire Dog Monument in Washington, D.C. She also traveled to Hollywood, where she mingled with big celebrities, including actress Betty White.

Sadie is healthy, but was getting stiff in her hips, so was retired. Sadie was the Means’ family dog before joining the CBI. Means sought the okay to have Sadie trained as arson dog. Now Sadie has returned to the family and is living with Means’ adult daughter, who also works in fire enforcement.

Sadie’s replacement, Riley, does not have the same prestigous past. But the new job is a second chance of sorts for him.

Riley dropped out of seeing-eye-school, but Means says Riley's skills are better suited to arson investigations, including an incredibly keen sense of smell.

Riley, who covers CBI’s northern Colorado zone, including Denver, attended an intensive national training program with Means run by the state police in Maine, and he graduated from Arson K-9 School in May. He's already responded to nearly 20 fires, including a suspected double murder.

Riley is with Means around the clock, but Means says the transition hasn’t been flawless.

“We’ve had my wife’s anniversary flowers trashed from one end of the house to the other and him sitting in the middle with physical evidence on his forehead,” Means says.